NAME

shutdown - close down the system at a given time

SYNOPSIS

shutdown [-] [-dfhknpr] time [warning-message ...]

DESCRIPTION

shutdown provides an automated shutdown procedure for superusers to nice-
ly notify users when the system is shutting down, saving them from system
administrators, hackers, and gurus, who would otherwise not bother with
such niceties. When the shutdown command is issued without options the
system is placed in single user mode at the indicated time after shutting
down all system services.
The options are as follows:
-d When used with -h or -r causes system to perform a dump. This op-
tion is useful for debugging system dump procedures or capturing
the state of a corrupted or misbehaving system. See savecore(8)
for information on how to recover this dump.
-f Create the file /fastboot so that the file systems will not be
checked by fsck(8) during the next boot. (See rc(8)).
-h The system is halted at the specified time when shutdown execs
halt(8).
-k Kick everybody off. The -k option does not actually halt the sys-
tem, but leaves the system multi-user with logins disabled (for
all but superuser).
-n When used with -h or -r prevents the normal sync(2) before stop-
ping the system.
-p The -p flag is passed on to halt(8), causing machines which sup-
port automatic power down to do so after halting. (Currently sup-
ported on some i386, luna88k, mac68k, macppc, sparc, sparc64 and
zaurus platforms.)
-r shutdown execs reboot(8) at the specified time.
time time is the time at which shutdown will bring the system down and
may be the word now (indicating an immediate shutdown) or specify
a future time in one of two formats: +number, or yymmddhhmm,
where the year, month, and day may be defaulted to the current
system values. The first form brings the system down in number
minutes and the second at the absolute time specified.
warning-message
Any other arguments comprise the warning message that is broad-
cast to users currently logged into the system.
- If '-' is supplied as an option, the warning message is read from
the standard input.
At intervals, becoming more frequent as apocalypse approaches and start-
ing at ten hours before shutdown, warning messages are displayed on the
terminals of all users logged in. Five minutes before shutdown, or im-
mediately if shutdown is in less than 5 minutes, logins are disabled by
creating /etc/nologin and copying the warning message there. If this file
exists when a user attempts to log in, login(1) prints its contents and
exits. The file is removed just before shutdown exits.
At shutdown time a message is written in the system log, containing the
time of shutdown, who initiated the shutdown and the reason. A terminate
signal is then sent to init to bring the system down to single-user state
(depending on above options). The time of the shutdown and the warning
message are placed in /etc/nologin and should be used to inform the users
about when the system will be back up and why it is going down (or any-
thing else).
You can cancel a scheduled shutdown with the kill(1) command by killing
the shutdown process.

FILES

/etc/nologin tells login not to let anyone log in
/fastboot tells rc(8) not to run fsck(8) during the next boot
/etc/rc.shutdown run by rc(8) before the system is shutdown